1. Field of the Invention
The invention relates to a pressure/temperature calculation apparatus of an internal combustion engine.
2. Description of Related Art
For example, Japanese Laid-open Patent Publication No. 2002-147279 (JP-A-2002-147279) discloses a method of calculating the pressure in an intake pipe of an internal combustion engine, based on the law of conservation of mass or the law of conservation of energy established between air flowing from the atmosphere into the intake pipe, and gas (e.g., exhaust gas) other than the air, which flows into the intake pipe.
As is understood from the whole description of JP-A-2002-147279, the method as disclosed in this publication has been developed on the assumption that the gas (other than the air) flowing into the intake pipe diffuses throughout the intake pipe. In fact, the gas (other than the air) flowing into the intake pipe does not diffuse uniformly throughout the intake pipe, but diffuses with a certain degree of distribution. Thus, the method as disclosed in JP-A-2002-147279 is still desired to be improved so that the pressure in the intake pipe can be calculated with higher accuracy.